JOVIAN SYSTEM DATA ANALYSIS PROGRAM PROPOSAL SUMMARY

1) Introduction. The NIMS investigation has provided spatial-spectral data sets of the Galilean Satellites. Spectra of the satellites have numerous as yet unidentified spectral features, as well as enigmatic water absorptions. Not only have these features not been identified, but their spatial locations have not been derived from the spatial coverage of the NIMS data set, except in a few cases. Extensive mineral maps are possible and waiting to be made with the NIMS data. 2) Past accomplishments. New Proposal. We have analyzed NIMS data with the NIMS team (e.g. see publications below). We have extensive experience with spectroscopic interpretation and probably have the most experience interpreting imaging spectroscopy data of any group in the world: we have processed literally tens of gigabytes of data involving hundreds of millions of spectra, and done extensive field verifications to prove materials mapping methods are accurate. We have extensive experioence in interpretation of planetary spectra. The NIMS data and our imaging spectroscopy and planetary spectrsocopy expertise will be brought together to analyse and map materials (ices, minerals and other chemicals) on the Galilean satellites of Jupiter. 3) Upcoming work. We will map the spatial location of spectral features in the NIMS imaging spectroscopy data using methods established with terrestrial imaging spectroscopy studies and measure spectra of cosmochemically possible materials (minerals and ices) in an environment chamber to identify them. Absorption bands shift and become narrower at lower temperatures, and the degree of these effects depends on the chemical bonds. Thus materials must be measured in the laboratory at temperature conditions appropriate to the planetary surface to determine if shifts and/or narrowing are important for proper interpretation of the NIMS spectra. We will measure a suite of minerals and ices to explore the possible effects, covering the ultraviolet to 5 microns (the NIMS spectral range) and beyond. The observed spectral features (both laboratory measured spectra of ices, minerals and other chemicals, as well as discovered features in the NIMS data) will be mapped for in the NIMS data set (all appropriate NIMS cubes, depending on spectral detectors used, and noise quality of the data). We will use the USGS tricorder (now tetracorder) algorithm, which can search for and produce spatial maps of thousands of materials. The total NIMS data set is small in comparison to terrestrial imaging spectroscopy data, for which we have processed literally tens of gigabytes of data involving hundreds of millions of spectra. Such materials maps can be used to address the evolution of the planetary surfaces and the processes which lead to their creation and ongoing modification. 4) Recent Papers: R.Carlson, W. Smythe, K. Baines, E. Barbinas, R. Burns, S. Calcutt, W. Calvin, R. Clark, et al., Near-Infrared Spectroscopy and Spectral Mapping of Jupiter and the Galilean Satellites: First Results from Galileo's Initial Orbit. Science, 274, 385-388, 1996. McCord, T.B., G.B. Hansen, R.N. Clark, P.D. Martin, C.A. Hibbits, F.P. Fanale, J.C. Granahan, M. Segura, D.L. Matson, T.V. Johnson, R.W. Carlson, W.D. Smythe, G.E. Danielson, and the NIMS team, Non-Water-Ice Constituents in the Surface Material of the Icy Galilean Satellites from the Galileo Near-Infrared Mapping Spectrometer Investigation, J. Geophys. Res., 103, 86 03-8626, 1998.